<!--
 * @Description: 盒子模型
 * @Author: rendc
 * @Date: 2021-06-29 08:52:00
 * @LastEditors: rendc
 * @LastEditTime: 2021-06-29 08:58:13
-->
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>盒子模型</title>
</head>

<body>
  <div style="
width: 200px;
height: 200px;
border: 1px solid royalblue;
padding: 20px;
margin: 20px;
box-sizing: border-box;
">

  </div>
</body>

</html>